Propeller



March 29, 1927. 1,622,835

c. o. MARSHALL PROPELLER Filed Sept. 8. 1921 Patented Mar, 29,1927.

NI E STATES PATENT 'oFFicE.

. *CHARLES O. MARSHALL, OF TOLEDQ, OHIO.

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Application ma September 8,1921. Serial No. 499,150.-

sirable features from the stan point of air craft propulsion. On the other hand, the high peripheralspeed which is necessary for economical turbine operation has heretofore made it seemimpracticable to provide an efiicient turbine having" a speed of rotation sufficiently low to ma e reduction gearing between the turbine and propeller unnecessary'and which at the same time is light and com act enough for installation in either air anes or dirigibles. In this invention the di culties outlined above are overcome by providing means wherebythe force exerted by motive fluid is caused to act upon the propeller itself at points having speed sufciently high to enable the energy of the fluid to be utilized without prohibitive loss.

Other objects and advantages will be apparent from the followin description,-1n which reference is had to t e accompanying drawings illustrating a preferred embodi-.

ment of my invention and wherein similar, reference numerals designate similar parts throu bout the several views.

In 518 drawings Figure 1 is an elevational view of a propeller in which is incorporated a turbine of the ancient Hero type;

Figure 2 is an enlarged vertical sectional view through the hub of the propeller and the mountin therefor showing a fragment of the prope er and a part of an inlet conduit for the motive fluid;

Fi re 3 is an enlarged sectional view taken substantially on the line 3-3 of Fi ure 1 and showing one of the nozzlesthroug which the motive fluid is discharged;

Fi re 4 is a perspective view, enlar ed to a esser extent, of an end of the prope ler shown in Fi 1; and

Figure 5 1s a similarly enlarged sectional view taken substantially on the line 5-5 of Figure 1.

Referring to the drawings in' detaii,.the frame 1 of the machine to be propelled is provided with a suitable bearing 2 within which the shaft 3 of the propeller hub 4 is rotatably mounted, anti-friction'balls being interposed, if desired, between the bearing and shaft. v

The hub 4 is provided with a suitable fixed hub flange 5 to which the propeller 6 is socured by means of bolts 7 and a clamping ring 8. The hub 4 is hollow, as shownin Fig- 'ure 2, its outer end being closed by a threaded. plug 9 and its inner-end communicating with the passage in the'hollow shaft 3, the i shaft in the form illustrated being shown as integral with the hub.

Extendin through the end of the bearing 2 and into the passage in the hollow shaft 3 is a pipe or conduit 10 through which the motive fluid is admitted to the hollow shaft and hub, the joint between, the pipe and shaft being fnade leak-proof, as by packing 11. From the hub the fluid passes through openings 12 and 13 into passages 14 and 15 in the blades of the propeller 6.

Adjacent the tips of each of its blades the propeller is provided with one or more discharge orifices or nozzles 16 leadin from the passages 14 and 15 and so forme as todirect the motive fluid rearwardly from the rear edges of theblades. The design of the nozzles may be varied to secure the maximum-effect from the reaction of the steam or gas. Preferably, however, they are of the slightly flaring type clearly illustrated in Figure 3. I have illustrated a plurality of circular nozzles,.but a single e ongated nozzle may, if desired, be substituted for the series of nozzles on each blade. The exterior of the portions of the blades containing the nozzles are preferably so shaped as to reduce to a minimum the resistance of the air to the rotation of the propeller.

Owing to the high speed at which the tips 'of the propeller travel, the percenta e of the energy of motive fluids which is utilized in turning the propeller compares favorably with the heat englnes of other types. Since the power is applied at the ends of the points where the greatest resistance to rotation occurs, the strain on the propeller and hub percentage that can be utilized in structure is much less than when the propeller is driven in the usual mannerby means of the shaft. The principal strains to be resisted in a propeller in which the power is applied at the tips of the blades are those due to its thrust. The strains caused by the action of the motive fluid in turning the propeller through the a1r are amply provided by Widening the portions of the propeller blades intermediate thei tips and the'hubs.

The motive fluid may be steam, products of combustion, or other gases, and'the power developed at the nozzles may be employed alone or in conjunction with power applied to the shaft. The turbo-propeller herein described may, for example, be operated with an internal combustion engine connected to the shaft, the exhaust gases being discharged through the propeller.

Although my invention is particularly adapted for use in aircraft, it is also applicable to the purpose of propelling wheeled vehicles, boats, missiles, and other devices.

The blades may be made of aluminum alloy or other suitable material and may, if desired, be built up of half portions, as indicated in Figs. 3 and 5, or the passages may be formed by tubular members embedded in the bodies of the blades.

\Vhile it will be apparent that the illust-rated embodiment of my invention herein disclosed is well calculated to adequately fulfill the objects primarily stated, it is to be understood that the invention is susceptible to variation, modification and change within the spirit and scope of the subjoinedclaims.

Having described my invention, I claim: 1. In a device of the class described, in combination, a high speed bladed propeller having passages therein and discharge nozzles for said passages, said nozzles being substantially smaller 1n cross sectlonal area than said passages and slightly flared at their discharging ends and being located only adjacent the tips of the propeller blades, and means for introducing motive fluid into said passages.

2. In a device of the class described, in

combination, a high speed bladed propeller,

each of the blades of said propeller having a passage therein and a discharge nozzle opening from the rear of the blade, said discharge nozzle being substantially smaller in cross sectional area than said passages and slightly flared and means for introducing a motive fluid into said passages.

3. In a device of the class described, in combination, a high speed two-bladed propeller comprising propeller blades provided with passages extending longitudinally thereof, the intermediate portions of said blades being wider than the portions adjacent their tips, said blades being provided with restricted slightly flaring orifices opening from said passages rearwardly adjacent the outer ends only for permitting the escape of motive fluid from said passages.

el. In a device of the class described, in combination, a high speed bladed propeller having a hollow hub with blades fixed thereto, said blades having passages opening into the interior of said hollow hub and nozzles adjacent their tips communicating with the passages and discharging rearwardly in respect of the direction of motion of said blades, said nozzles being substantially smaller in cross sectional area than said passages and slightly flared, a hollow shaft extending axially from said hub, the interior of said shaft communicating with the interior of said hub, a support for said shaft, bearings secured to said support, said shaft being journaled in said bearings, and means for introducing a motive fluid into said hollow shaft.

CHARLES O. MARSHALL. 

